The present invention relates to a three dimensional real time apparatus for imaging an ocular retina and more specifically to a three dimensional real-time apparatus for imaging an ocular retina wherein the optical system is so arranged that, with reference to the retina, the incident angles of the laser beams irradiated on the retina at respective moments and the output angles of imaginary or extended lines of the same laser beams reflected from the retina may agree with each other in both the vertical and horizontal direction to allow three dimensional real-time observation for the retina.
The eyeball mainly consists of a crystalline lens, retinal, glass body, sclera, cornea and the like. The retina of them is a thin and almost transparent membrane of three-dimensional structure with the thickness of 170xcexc to 500xcexc and particularly it can become somewhat thicker or thinner due to retinal edema under a pathologic condition. Currently two dimensional image of retina is used for diagnosis and treatment. However, in order to clarify pathological retinal phenomena and observe the dynamic changes, real-time three dimensional image scanning of the retina is needed. Nevertheless, it is true that no satisfactory image technology has been developed so far.
The equipments currently available, which allow for approximate three dimensional image of the retina at least partially, may be mentioned as follows:
First, there is a RTA(Retina Thickness Analyzer). This RTA apparatus scans the cross sections of the retina, wherein the distance between the light reflecting on the front of a retina and that reflecting on the back of the retina is analyzed, so that the thickness of the retina may be represented as in contour lines in a map. These equipments are defective, however, in that these simply show the vertical irregularities of a retina by using lines based on non-real time scanning, without permitting a practical observation of the retina.
Second, the SLO(Scanning Laser Ophthalmoscope) has also been developed. This equipment is a two dimensional retinal imaging apparatus based on real time scanning lines by irradiating laser ray on one point of a retina at an instant to form the corresponding image on a monitor. This equipment is also problematic because this does not permit three dimensional real-time observation of a retinal image as well.
Third, the OCT(Optical Coherence Tomography) is also available. This OCT apparatus realizes a high resolution in representing the cross sections of a retina in the form of lines. Similarly, this equipment is not operated on real-time scanning and can not provide three dimensional image beside the retinal cross section on a certain line.
Fourth, the HRT(Heidelberg Retinal Tomography) is also available. This equipment is not also based on the real-time scanning and further has the problem of simply representing overall retinal irregularities in the form of grids.
Therefore, the object of the invention, in consideration of the above-described drawbacks with the conventional arts, is to provide a three dimensional real-time apparatus for imaging ocular retina wherein the optical system is so arranged that, with reference to the retina, the incident angle of the laser beams irradiated on the retina at respective moments and the output angles (radiation angle) of imaginary or extended lines of the laser beams reflected from the retina may agree with each other in both the vertical and horizontal direction to allow three dimensional real-time observation for the retina.
The above object is achieved according to the invention by a three dimensional real-time apparatus for imaging an ocular retina which comprises a laser generating device for generating laser beams, an optical means for making the output angles of imaginary or extended lines of the laser rays reflected from the retina agree with the incident angles of the same laser beams irradiated on the retina at respective moments in both the vertical and horizontal direction and a three dimensional imaging means for converting the image of the retina extracted from the optical means to a real-time three dimensional image.